红鳍东方鲀生长激素释放激素(GHRH)基因多态性及其与生长性状的关联分析

Correlation analysis between single nucleotide polymorphisms(SNPs)of GHRH gene and growth traits of tiger puffer Takifugu rubripes

为研究生长激素释放激素(growth hormone-releasing hormone,GHRH)基因对红鳍东方鲀Takifugu rubripes生长性状的影响,设计4对可覆盖GHRH基因全序列的PCR引物,采用直接测序法对序列进行分析比对以筛选多态位点。试验群体为随机挑选的219尾红鳍东方鲀,于该群体的6月龄及12月龄时测量其体质量、体长、体高等10个生长相关性状,随后将筛选出的多态位点与生长性状进行关联分析,并进行连锁不平衡及双倍型分析。结果表明:共筛选出7个SNPs位点,分别为C81T、G315C、C1083T、A1524G、G2107A、T2125C和G2256A,其中,C81T、G315C和A1524G 3个位点的多态性与大多数生长性状均存在显著关联性(P<0.05);G2256A与T2125C,G207A与C083T位点均处于连锁不平衡状态,但并非完全连锁;6月龄群体中,双倍型D4和D5的体质量平均值显著高于D3(P<0.05),12月龄群体中,双倍型D5的体质量平均值显著高于D3(P<0.05)。研究表明,C81T、G315C和A1524G 3个位点是对红鳍东方鲀生长有正向影响的优势位点,6月龄群体中,双倍型D4和D5为优势基因型,12月龄群体中,双倍型D5为优势基因型,在后续红鳍东方鲀选育过程中可以优先选择这些位点和基因型。

The purpose of this experiment was to investigate the effect of GHRH(growth hormone-releasing hormone)gene on the growth traits of tiger puffer Takifugu rubripes and to provide reference for molecular assisted breeding.The sequences of GHRH gene were analyzed and aligned in tiger puffer whose body mass,body length,body height and other 10 growth-related traits were measured at the age of 6 months and 12 months after breeding by designed four pairs of PCR primers to cover the whole sequence of GHRH gene to screen the single nucleotide polymorphisms(SNPs).Subsequently,association analysis was performed between the SNPs and growth traits as well as linkage disequilibrium and diplotype analysis.The results showed that a total of seven SNPs sites were screened out,including C81T,G315C,C1083T,A1524G,G2107A,T2125C and G2256A,in which C81T,G315C and A1524G were significantly correlated with most growth traits.G2256A and T2125C,G207A and C083T were in linkage disequilibrium but not complete linkage.The diplotypes D4 and D5 had significantly higher mean body mass than the diplotype D3 did(P<0.05).The three SNPs of C81T,G315C and A1524G were shown to be dominant loci with a positive effect on the growth of tiger puffer,and the diplotypes D4 and D5 were the dominant genotypes in 6 month old population,while the diplotype D5 was the dominant genotype in 12 month old population,which was preferred in the subsequent breeding process of tiger puffer.